Ascomycetes (Sac fungi) MCQ - Practice Questions with Answers

• Mycelium is filamentous, septate and branched. Cells can be monokaryotic as well as dikaryotic.
• Ascomycetes show unicellular (yeast) as well as multicellular organisms.
• Ascomycetes can be saprophytic, parasitic, decomposers etc.
• Ascomycetes reproduce asexually by means of conidia formation. These conidia are formed on specialized hyphae called conidiophores.
• Sexual reproduction takes place by gametangial contact.
• The male sex organ is antheridium and the female is called as Ascogonium.
• Male nuclei migrate into female gametangium and form the dikaryotic cell. This dikaryotic cell divide and forms dikaryotic mycelium. These mycelial hyphae are called as ascogenous hyphae.
• These form fruiting bodies called as Ascocarps. Ascocarp has asci. The two nuclei of each ascus fuse and form a diploid nucleus. This nucleus undergoes reduction division and forms haploid nuclei. These nuclei accumulate cytoplasm around them and develop into haploid ascospores which on germination develop into monokaryotic mycelium.
• The fruiting body of ascomycetes is called ascocarp. It can be of various shapes. 
• Globose and closed ascocarp is called as Cleistothecium (Penicillium).
•  Flask shaped ascocarp with an apical opening is called as Perithecium (Aspergillus, Claviceps).
• Cup-shaped ascocarp is called as Apothecium (Peziza).

Examples of Ascomycetes:

• Saccharomyces cerevisiae- Yeast is economical very important in the brewing industry, baking industry etc.
• Aspergillus flavus- It is used to produce aflatoxins. 
• Penicillium- also called blue-green mould. It was used for obtaining first ever antibiotic penicillin.  
• Claviceps purpurea- causes ergot of rye and other cereals. It is used to obtain lysergic acid which used for treating uterine haemorrhage after childbirth.
• Neurospora- also called pink fungi. It is used for conducting genetics experiments.
• Morels (Morchella) and truffles (Tuber) are edible.